1. Field of the Invention
The invention is concerned with an improvement in a machine tool gripping assembly. The improvement is in the form of a floating collar in a bore within a housing, the floating collar being adjacent the spindle gripping end of a plurality of resilient leaves which are attached at one end to a collet and are separated at a spindle gripping end thereof, said collet being slidable toward and retractable from a spindle facing end portion of the bore. The floating collar includes an annular cam surface and each of the leaves has a matching cam surface adjacent the spindle gripping end thereof whereby the two cam surfaces slide against one another as the collet is slid into and out of the bore. An inner surface of the collar urges the spindle gripping end of the leaves towards one another when the collet is retracted into the bore and an outer generally cylindrical surface of the collar floats clear of the spindle facing end portion of the bore. Means are provided supported by the bore adjacent the spindle facing end portion thereof for stopping the collar from sliding into the bore and means are provided for preventing the collar from sliding out of the spindle facing end portion of the bore, the ends of the collar floating clear of the stopping means and of the preventing means. In this manner, failure of the leaves due to the added stress caused by misalignment thereof relative to the spindle of the machine tool being gripped is virtually eliminated.